Hydrogel liquid precursor, liquid set for three-dimensional modeling, hydrogel modeling object, and method of manufacturing three-dimensional object

ABSTRACT

A hydrogel liquid precursor includes an inorganic mineral and a monomer, wherein the inorganic mineral accounts for 15 percent by mass or more of the hydrogel liquid precursor, wherein the hydrogel liquid precursor has an initial viscosity of 20 mPa·s or less at 25 degrees C., and wherein the hydrogel liquid precursor has a ratio of a two-week viscosity to the initial viscosity of from 0.90 to 1.10, the two-week viscosity representing a viscosity of the hydrogel liquid precursor at 25 degrees C. after being left at 50 degrees C. for two weeks.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is based on and claims priority pursuant to 35U.S.C. § 119 to Japanese Patent Application No. 2015-057312 filed onMar. 20, 2015, in the Japan Patent Office, the entire disclosure ofwhich is hereby incorporated by reference herein.

BACKGROUND

Technical Field

The present invention relates to a hydrogel liquid precursor, a liquidset for three-dimensional modeling, a hydrogel modeling object using theliquid or the liquid set, and methods of manufacturing 3D objects usingthe liquid or the liquid set.

Background Art

Small lot production of a complex and fine object is increasinglydemanded. Of these 3D objects, internal organ model for procedurepractices for surgery are strongly demanded, reproducing softness to adegree that the model can be cut open by a surgical scalpel, bite andtouch of the object extremely close to those of internal organs, and atrue-to-life form of the internal organ of individual patients. Hydrogelis a good candidate as the model because softness and touch of such ahydrogel are close to those of real internal organs.

SUMMARY

According to the present invention, provided is an improved hydrogelliquid precursor including an inorganic mineral and a monomer, whereinthe inorganic mineral accounts for 15 percent by mass or more of thehydrogel liquid precursor, wherein the hydrogel liquid precursor has aninitial viscosity of 20 mPa·s or less at 25 degrees C., and wherein thehydrogel liquid precursor has a ratio of a two-week viscosity to theinitial viscosity of from 0.90 to 1.10, the two-week viscosityrepresenting a viscosity of the hydrogel liquid precursor at 25 degreesC. after being left at 50 degrees C. for two weeks.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Various other objects, features and attendant advantages of the presentinvention will be more fully appreciated as the same becomes betterunderstood from the detailed description when considered in connectionwith the accompanying drawings in which like reference charactersdesignate like corresponding parts throughout and wherein:

FIG. 1 is a schematic diagram illustrating an example of a laminatemineral and a state in which the laminate mineral is dispersed in water;

FIG. 2 is a schematic diagram illustrating an example of the device formanufacturing a 3D object for use in the method of manufacturing a 3Dobject according to an embodiment of the present invention;

FIG. 3 is a schematic diagram illustrating another example of the devicefor manufacturing a 3D object for use in the method of manufacturing a3D object according to an embodiment of the present invention;

FIG. 4A is a schematic diagram illustrating an example of the 3D objectmanufactured by the method of manufacturing a 3D object according to anembodiment of the present invention; and

FIG. 4B is a schematic cross sectional view of the 3D object illustratedin FIG. 4A.

DETAILED DESCRIPTION

Internal organ model for procedure practices for surgery are stronglydemanded, reproducing softness to a degree that the model can be cutopen by a surgical scalpel, bite and touch of the object extremely closeto those of internal organs, and a true-to-life form of the internalorgan of individual patients. Hydrogel is a good candidate as the modelbecause softness and touch of such a hydrogel are close to those of realinternal organs. A specific example of the hydrogel contains water inthe three-dimensional network structure formed by compounding a laminatemineral and a polymer.

However, such a hydrogel is relatively soft (i.e., modulus of elasticityis low) so that a relatively hard hydrogel (i.e., modulus of elasticityis high) is not obtained

The present disclosure is to provide a hydrogel liquid precursor havinga good storage property and suitable to manufacture a hydrogel modelingobject having a complex inner structure including a modeling portionhaving a high modulus of elasticity shaped by a hydrogel modeling objecthaving a high modulus of elasticity with a modeling portion having a lowmodulus of elasticity disposed at an arbitrary area.

Hydrogel Liquid Precursor

The hydrogel liquid precursor of the present disclosure includes aninorganic mineral and a monomer, preferably a phosphonic acid compound,and other optional components.

Inorganic Mineral

The inorganic mineral is contained to enhance the modulus of elasticity(80 percent compressive stress-strain or modulus of compressiveelasticity) of a hydrogel modeling object.

The inorganic mineral has no specific limit and is suitably selected toa particular application. For example, laminate mineral is usable.

The laminate mineral includes crystal having a two-dimensional disk-likeform having unit lattices in the crystal. Single layers of the laminatemineral are piled up as illustrated on the upper part of FIG. 1 and whenthe laminate mineral is dispersed in water, the mineral is separatedinto each signal layer having a disk-like form as illustrated on thelower part of FIG. 1.

The laminate mineral has no particular limit and, for example, waterswellable laminate clay minerals are suitable.

Examples of such clay minerals are water swellable smectite and waterswellable mica. Specific examples thereof include, but are not limitedto, water swellable hectorite, water swellable montmorillonite, waterswellable saponite, and water swellable synthesized mica. These can beused alone or in combination. Of these, water swellable hectorite ispreferable to obtain hydrogel modeling objects having high elasticity.

Water swellable hectorite can be appropriately synthesized or isavailable on market. Specific examples of the synthesized hectorite(laponite XLG, manufactured by RockWood), SWN (manufactured by CoopChemical Ltd.), and fluorinated hectorite SWF (manufactured CoopChemical Ltd.). Of these, synthesized hectorite is preferable in termsof modulus of elasticity of a hydrogel modeling object.

“Water swellable” means that water molecules are inserted between layersof the inorganic mineral and the inorganic mineral is dispersed asillustrated in FIG. 1.

Since the modulus of elasticity and hardness of a hydrogel modelingobject are set to a value or higher, the content of the inorganicmineral of a hydrogel modeling object accounts for 15 percent by mass ormore of the total content of the hydrogel liquid precursor. Also, interms of viscosity (inkjet dischargeability) of the hydrogel liquidprecursor and dispersibility of the inorganic mineral in the hydrogelliquid precursor, the content of the inorganic mineral preferablyaccounts for 15 percent by mass to 40 percent by mass and morepreferably 15 percent by mass to 25 percent by mass.

Monomer

The monomer is not particularly limited as long as the monomer iscapable of cross-linking with the inorganic mineral. For example, watersoluble monomers are preferable.

Water-solubility of the water soluble monomer means, for example, when 1g of a homopolymer of the water soluble monomer is mixed and stirred in100 g of water at 30 degrees C., 90 percent by mass or more of thehomopolymer is dissolved therein.

The monomer is a compound having at least one unsaturated carbon-carbonbond and includes, for example, a mono-functional monomer and amulti-functional monomer. Furthermore, the multi-functional monomerincludes a bi-functional monomer and a tri- or higher functionalmonomer.

As the monomer, an active energy ray polymerization type monomer ispreferable in terms of modeling property of the hydrogel modelingobject.

The mono-functional monomer is a compound having a single unsaturatedcarbon-carbon bond and specific examples thereof includes, for example,acrylamides, N-substituted acrylamide derivatives, N,N-di-substitutedacrylamide derivatives, N-substituted methacrylamide derivatives,N,N-di-substituted methacrylamide derivatives, and other mono-functionalmonomers. These can be used alone or in combination.

The N-substituted acrylamide derivatives, N,N-di-substituted acrylamidederivatives, N-substituted methacrylamide derivatives, andN,N-di-substituted methacrylamide derivatives include, for example,N,N-dimethyl acryl amide (DMAA) and N-isopropyl acryl amide.

Specific examples of the other mono-functional monomers includes, butare not limited to, 2-ethylhexyl(meth)acrylate (EHA),2-hydroxyethyl(meth)acrylate (HEA), 2-hydroxypropyl(meth)acrylate (HPA),acryloylmorpholine (ACMO), caprolactone-modified tetrahydrofurfuryl(meth)acrylate, isobonyl(meth)acrylate, 3-methoxybutyl(meth)acrylate,tetrahydrofurfuryl(meth)acrylate, lauryl(meth)acrylate,2-phenoxyethyl(meth)acrylate, isodecyl(meth)acrylate,isooctyl(meth)acrylate, tridecyl(meth)acrylate,caprolactone(meth)acrylate, ethoxyfied nonylphenol(meth)acrylate, andurethane(meth)acrylate. These can be used alone or in combination.

Water soluble organic polymers having an amide group, an amino group, ahydroxyl group, a tetramethyl ammonium group, a silanol group, an epoxygroup, etc. are obtained by polymerizing the mono-functional monomersmentioned above.

Water soluble organic polymers having an amide group, an amino group, ahydroxyl group, a tetramethyl ammonium group, a silanol group, an epoxygroup, etc. are advantageous to maintain the strength of a hydrogelmodeling object.

The content of the mono-functional monomer is not particularly limitedbut it is preferably from one percent by mass to 10 percent by mass andmore preferably from 1 percent by mass to 5 percent by mass to the totalcontent of the hydrogel liquid precursor to a particular application.When the content is in the range of from one percent by mass to 10percent by mass, dispersion stability of the inorganic mineral in ahydrogel liquid precursor is maintained and drawing property of ahydrogel precursor object is enhanced. The drawing property means thatwhen a hydrogel modeling object is drawn, the hydrogel modeling objectis not fractured (broken) but extended.

Specific examples of the bi-functional monomers include, but are notlimited to, tripropylene glycol di(meth)acrylate, triethylene glycoldi(meth)acrylate, tetraethylene glycol di(meth)acrylate, polypropyleneglycol di(meth)acrylate, neopentyl glycol hydroxy pivalic acid esterdi(meth)acrylate (MANDA), hydroxypivalic acid neopentyl glycol esterdi(meth)acrylate (HPNDA), 1,3-butanediol di(meth)acrylate (BGDA),1,4-butanediol di(meth)acrylate (BUDA), 1,6-hexane diol di(meth)acrylate(HDDA), 1,9-nonane di(meth)acrylate, diethylene glycol di(meth)acrylate(DEGDA), neopentyl glycol di(meth)acrylate (NPGDA), tripropylene glycoldi(meth)acrylate (TPGDA), caprolactone-modified hydroxy pivalic acidneopentyl glycol ester di(meth)acrylate, propoxinated neopentyl glycoldi(meth)acrylate, ethoxy-modified bisphenol A di(meth)acrylate,polyethylene glycol 200 di(meth)acrylate, polyethylene glycol 400di(meth)acrylate, and methylenebis acrylamide. These can be used aloneor in combination.

Specific examples of the tri-functional monomers include, but are notlimited to, trimethylol propane tri(meth)acrylate (TMPTA),pentaerythritol tri(meth)acrylate (PETA), tirallyl isocyanate,tris(2-hydroxyethyl)isocyanulate tri(meth)acrylate, ethoxyfiedtrimethylol propane tri(meth)acrylate, propoxyfied trimethylol propanetri(meth)acrylate, and propoxyfied glyceryl tri(meth)acrylate. These canbe used alone or in combination.

Specific examples of the tri- or higher monomers include, but are notlimited to, pentaerythritol tetra(meth)acrylate, ditrimethylolpropanetetra(meth)acrylate, dipentaerythritolhydroxypenta(meth)acrylate, ethoxyfied pentaerythritol tetra(meth)acrylate, penta(meth)acrylate ester, and dipentaerythritolhexa(meth)acrylate (DPHA). These can be used alone or in combination.

The content of the multi-functional monomer is preferably from 0.001percent by mass to 1 percent by mass and more preferably from 0.01percent by weight to 0.5 percent by mass to the total content of thehydrogel liquid precursor. When the content is in the range of from0.001 percent by mass to 1 percent by mass, it is possible to controlthe modulus of elasticity (80 percent compressive stress-strain ormodulus of compressive elasticity) and hardness of the obtained hydrogelmodeling object in a suitable range.

Phosphonic Acid Compound

The phosphonic acid compound is suitable to improve storage stability ofthe hydrogel liquid precursor.

The phosphonic acid compound includes, for example, phosphonic acid,salts of phosphonic acid, and intermediates thereof.

The phosphonic acid compound has no particular limit and the compoundrepresented by the following Chemical formula 1 is preferable.

In the Chemical formula 1, R represents a substituted or non-substituteddivalent substitution group.

Specific examples of the divalent substitution group of R in theChemical formula 1 include, but are not limited to, oxygen atom, sulfuratom, and alkyl groups. Of these, alkyl groups are preferable. When R isan alkyl group, the phosphoric acid compound is not hydrolyzed over timeunlike pyrophosphoric acid where R is an oxygen atom. Therefore, theinorganic mineral is stably dispersed in the hydrogel liquid precursor,thereby improving the storage stability of the hydrogel liquidprecursor.

The alkyl group of R in the Chemical formula 1 has not particular limit.In terms of adsorption to the inorganic mineral, —(R₁)C(R₂)— (where R₁and R₂ each, independently represent substituted or non-substitutedalkyl groups) is preferable.

R₁ and R₂ each, independently represent substituted or non-substitutedalkyl groups. Specific examples thereof include, but are not limited to,methyl group and ethyl group. Specific examples of the substitutiongroup of the alkyl group include, but are not limited to, hydroxy group,amino group, halogen atoms, and alkyl groups. Of these, —(OH)C(CH₃)— ispreferable in terms of storage stability.

Specific examples of the compound represented by the Chemical formula 1include, but are not limited to, the compound (etidronic acid),alendronic acid, methylene diphosphonic acid, pyrophosphoric acid,phytic acid, nitrilotris methylene phosphonic acid (NTMP), and saltsthereof. Of these, to obtain a hydrogel modeling object having a highmodulus of elasticity, etidronic acid, alendronic acid, methylenediphosphonic acid, and salts thereof are preferable and etidronic acidand sodium salt of etidronic acid are more preferable.

The content of the phosphonic acid compound is preferably from 0.1 partsby mass to 10 parts by mass to 100 parts of the inorganic mineral interms of improvement of dispersibility of the inorganic mineral. Whenthe content is in the range of from 0.1 parts by mass to 10 parts bymass, adsorption to the inorganic mineral is sufficient, therebystrengthening the mutual action between the monomer and the inorganicmineral. As a result, the modulus of elasticity (80 percent compressivestress-strain or compressive modulus of elasticity) of a formed hydrogelmodeling object tends to increase.

Solvent

The solvent has no particular limit. For example, solvents capable ofdissolving the material of the hydrogel liquid precursor are suitable.Examples thereof are water and organic solvents. These can be used aloneor in combination. Of these, water is preferable.

Water

As the water, deionized water, ultrafiltered water, reverse osmosiswater, pure water such as distilled water, and ultra pure water can beused. It is suitable to dissolve or disperse other components such asorganic solvents in the water to impart moisturizing property,antibiotic property, or electroconductive property and adjust hardness.

The content of the water has no particular limit and can be selected toa particular application.

Organic Solvent

The organic solvent is preferably aqueous and for example, alcohols suchas ethanol, ethers, and ketones are suitable.

The organic solvent has no particular limit. Specific examples of theorganic solvent include, but are not limited to, 1,2,6-hexane triol,1,2-butanediol, 1,2-hexane diol, 1,2-pentanediol,1,3-dimethyl-2-imidazolidinone, 1,3-butanediol, 1,3-propane diol,1,4-butanediol, 1,5-pentanediol, 1,6-hexane diol,2,2-dimethyl-1,3-propane diol, 2,3-butanediol, 2,4-pentanediol,2,5-hexane diol, 2-ethyl-1,3-hexane diol, 2-pyrolidone,2-methyl-1,3-propane diol, 2-methyl-2,4-pentanediol,3-methyl-1,3-butanediol, 3-methyl-1,3-hexane diol,N-methyl-2-pyrolidone, N-methyl pyrrolidinone,β-buthoxy-N,N-dimethylpropione amide, β-methoxy-N,N-dimethyl propioneamide, γ-butylolactone, ε-caprolactam, ethylene glycol, ethyleneglycol-n-butyl ether, ethylene glycol-n-propylether, ethylene glycolphenyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycolmonoethyl ether, glycerin, diethylene glycol, diethyleneglycol-n-hexylether, diethylene glycolmethylether, diethylene glycolmonoethyl ether, dietheylene glycol monobutyl ether, diethylene glycolmonomethyl ether, diglycerin, dipropylene glycol, dipropylene glycol,dipropylene glycol-n-propylether, dipropylene glycol monomethylether,dimethylsulfoxide, sulfolane, thiodiglycol, tetraethylene glycol,triethylene glycol, triethylene glycol ethylether, triethylene glycoldimethylether, triethylene glycol monobutylether, triethylene glycolmethylether, tripropylene glycol, tripropylene glycol-n-propylether,tripropylene glycol methylether, trimethylol ethane, trimethylolpropane, propylpropylene diglycol, propylene glycol, propyleneglycol-n-butylether, propylene glycol-t-butylether, propyleneglycolphenylether, propylene glycol monoethylether, hexylene glycol,polyethylene glycol, and polypropylene glycol. These can be used aloneor in combination.

The content of the organic solvent is preferably from 1 percent by massto 40 percent by mass to the total amount of a hydrogel liquid precursorand more preferably from 5 percent by mass to 20 percent by weight.

Other Components

The other optional components have no particular limit. For example,known photopolymerizable initiators, surfactants, colorants,stabilizers, water-soluble resins, alcohols having low boiling points,surface treatment agents, viscosity adjusting agents, adherenceimparting agents, anti-oxidants, anti-aging agents, cross-linkingpromoters, ultraviolet absorbents, plasticizers, and preservatives.

Property of Hydrogel Liquid Precursor

The surface tension of the hydrogel liquid precursor at 25 degrees C. isnot particularly limited and is preferably from 20 mN/m to 45 mN/m andmore preferably from 25 mN to 34 mN/m.

When the surface tension is 20 mN/m or more, dischargeability of thehydrogel liquid precursor is good when modeling a 3D object. When thesurface tension is 45 mN/m or less, the property of the hydrogel liquidprecursor is good when a discharging nozzle, etc. is filled with thehydrogel liquid precursor.

The surface tension can be measured by a surface tensiometer (automaticcontact angle DM-701, manufactured by Kyowa Interface Science Co.,LTD.), etc.

The viscosity of the hydrogel liquid precursor at 25 degrees C. atnormal pressure is preferably 20 mPa·s or less and more preferably from6 mPa·s to 12 mPa·s. The normal pressure means an air pressure of from900 hPa to 1,100 hPa.

When the viscosity is in the range of from 3 mPa·s to 20 mPa·s,dischargeability of the hydrogel liquid precursor is good when modelinga 3D object.

The viscosity can be measured by, for example, a rotation viscometer(VISCOMATE VM-150 III, manufactured by TOKI SANGYO CO., LTD.) in a 25degrees C. and normal pressure environment.

When the viscosity of the hydrogel liquid precursor at 25 degrees C. isdefined as the initial viscosity and the two-week viscosity is definedas the viscosity at 25 degrees C. of the hydrogel liquid precursor leftat 50 degrees C. for two weeks, the ratio of the two week viscosity tothe initial viscosity is from 0.90 to 1.10.

When the ratio of the two week viscosity to the initial viscosity isfrom 0.90 to 1.10, storage stability of the hydrogel liquid precursor isappropriate and viscosity of the hydrogel liquid precursor containing alarge amount of the inorganic mineral is maintained low, so that thehydrogel liquid precursor is suitably used for a liquid set for 3Dmodeling and a manufacturing method of a 3D modeling object.

The ratio of the two week viscosity to the initial viscosity can becalculated as follows.

First, the hydrogel liquid precursor is prepared, placed in apolypropylene bin (50 ml), left in a constant temperature tank at 50degrees C. for 24 hours, and thereafter taken out from the tank to becooled down to room temperature (25 degrees C.). Thereafter, the initialviscosity is measured at normal pressure.

In the case of the two week viscosity, the hydrogel liquid precursor isplaced in a polypropylene bin (50 ml), left in a constant temperaturetank at 50 degrees C. for two weeks, and thereafter taken out from thetank to be cooled down to room temperature (25 degrees C.) followed bymeasuring at normal pressure.

From the two-week viscosity and the initial viscosity, the ratio of thetwo-week viscosity to the initial viscosity is calculated.

The hydrogel liquid precursor of the present disclosure can be suitablyused for methods of manufacturing various hydrogel modeling objects andin particular the hydrogel modeling object of the present disclosure,the liquid set for 3D modeling of the present disclosure, and the methodof manufacturing 3D object of the present disclosure.

Liquid Set for 3D Modeling

The liquid set for 3D modeling of the present disclosure contains ahydrogel liquid precursor (first hydrogel liquid precursor) describedabove, a second hydrogel liquid precursor, preferably a liquid for ahard modeling object (support), and optionally other components.

The liquid set for 3D modeling makes it possible to provide a hydrogelmodeling object having portions with different elasticity (80 percentcompressive stress-strain or modulus of compressive elasticity), whichis suitable as internal organ model.

First Hydrogel Liquid Precursor

The hydrogel liquid precursor of the present disclosure can be used asthe first hydrogel liquid precursor.

Second Hydrogel Liquid Precursor

The second hydrogel liquid precursor contains a (second) inorganicmineral and a (second) monomer and has a different composition from thefirst hydrogel liquid precursor. The inorganic minerals and the monomerscontained in the hydrogel liquid precursor of the present disclosure canbe used as the second inorganic mineral and the second monomer

“The second hydrogel liquid precursor has a different composition” meansthat either or both of the kind and the content of the compositionconstituting the second hydrogel liquid precursor is different fromthose of the first hydrogel liquid precursor.

It is preferable that the first hydrogel liquid precursor and the secondhydrogel liquid precursor should form hydrogel modeling objects havingdifferent modulus of elasticity (80 percent compressive stress-strain ormodulus of compressive elasticity) when these liquids are cured. Forthis reason, it is possible to efficiently manufacture a 3D modelingobject having modeled portions having different modulus of elasticity.

Liquid for Hard Modeling Object (Support)

The liquid for a hard 3D object (support) is used in a method ofmanufacturing a 3D object and becomes a hard modeling object (support)to support a hydrogel modeling object during manufacturing in themanufacturing process of the 3D object. The liquid for a hard modelingobject contains a curable material, preferably a photopolymerizableinitiator, and other optional components but no water or inorganicmineral.

Curable Materials

The curable material is preferably a compound cured in polymerizationreaction caused by irradiation of active energy ray (ultraviolet ray,electron beam, etc.), heating, etc. For example, active energy raypolymerizable compounds and thermally-curable compounds are suitable. Ofthese, materials being liquid at 25 degrees C. are preferable.

The active energy ray polymerizable compound is a monomer having aradically-polymerizable unsaturated bond in the molecule structure and arelatively low viscosity. It is possible to select from themulti-functional monomers or mono-functional monomers used in the firsthydrogel liquid precursor and the second hydrogel liquid precursor to aparticular application. These can be used alone or in combination.

The content of the curable material has no particular limit and can beselected to a particular application.

Other Components

The other optional components have no particular limit. For example,colorants, water-soluble resins, alcohols having low boiling points,surfactants, viscosity adjusting agents, adherence imparting agents,anti-oxidants, anti-aging agents, cross-linking promoters, ultravioletabsorbents, plasticizers, and dispersants.

The liquid set for 3D modeling of the present disclosure can be suitablyused for manufacturing various 3D modeling objects and in particular,complex and fine 3D modeling objects having modeled portions havingdifferent modulus of elasticity (80 percent compressive stress-strainand modulus of compressive elasticity) such as internal organ model.

Also, the liquid is particularly suitable for the method ofmanufacturing a 3D object of the present disclosure and the hydrogelmodeling object of the present disclosure.

Method of Manufacturing 3D Object

The method of manufacturing a 3D object of the present disclosure is tomanufacture a hydrogel modeling object using the hydrogel liquidprecursor or the liquid set for 3D modeling.

By the method of manufacturing a 3D object, complex and fine 3D objectsrepresented by internal organ models are simply and efficientlymanufactured.

The method of manufacturing a 3D object relating to a first embodimentincludes a step of manufacturing a hydrogel modeling object using thehydrogel liquid precursor or the first hydrogel liquid precursor in theliquid set for 3D modeling and other optional steps such as curing thehydrogel liquid precursor or the first hydrogel liquid precursor.

The step of curing the liquid for 3D modeling is to cure the (first)hydrogel liquid precursor.

As the device to cure the (first) hydrogel liquid precursor, ultraviolet(UV) irradiating lamps, electron beam irradiators, etc. are used. Thedevice to cure the (first) hydrogel liquid precursor preferably includesan ozone removing mechanism.

The ultraviolet irradiating lamp includes, for example, a high pressuremercury lamp and an ultra high pressure mercury lamp, and a metal halidelamp.

The ultra-high pressure mercury lamp is a point light source but if theDeepUV type in which the lamp is combined with an optical system toimprove the light use efficiency is used, the lamp is capable ofirradiating a short-wavelength modeling portion.

The metal halide lamp is suitable for a colored material because thecolored material absorbs light so that irradiation of light outside theabsorption band is possible for curing. Halogenized compounds of metalsuch as Pb, Sn, and Fe are used and can be selected to the absorptionspectrum of a photopolymerization initiator.

The lamp for use in curing has no particular limit. Lamps available onmarket such as H lamp, D lamp, or V lamp, (manufactured by FusionSystem) can be used to a particular application.

The method of manufacturing a 3D object relating to a second embodimentincludes a step of placing the (first) hydrogel liquid precursor on abase plate (substrate) or a previously formed layer of the (first)hydrogel liquid precursor, curing the (first) hydrogel liquid precursoron the base plate or the layer, and other optional steps.

The method of placing the (first) hydrogel liquid precursor on the baseis not particularly limited. Preferably, droplets formed of the (first)hydrogel liquid precursor are applied to target positions withappropriate precision by the method. For example, a dispenser method, aspray method, or an inkjet method can be suitably selected to aparticularly application. Known devices are used to execute the method.Of these, the inkjet method is particularly preferable in the presentdisclosure. The inkjet method has a good quantitative property incomparison with the spray method and a wider application area incomparison with the dispenser method. Accordingly, the inkjet method ispreferable to accurately and efficiently form a complex hydrogelmodeling object.

With regard to the device to cure the (first) hydrogel liquid precursor,the detailed description is omitted because the curing device is thesame as the device to cure the (first) hydrogel liquid precursorspecified in the method of manufacturing a 3D object relating to thefirst embodiment.

The (first) hydrogel modeling object after curing has athree-dimensional network structure formed by complexing a polymerpolymerized from the mono-functional monomer or the multi-functionalmonomer and the inorganic mineral. The three-dimensional networkstructure encloses water and components dissolved in the water.

In the method of manufacturing a 3D object relating to the secondembodiment, each step described above may be repeated multiple times.When modeling an object by the repetition, the number of the repetitionis not simply determined because the number depends on the side, form,structure, etc. of the 3D object to be manufactured. However, if thethickness per layer is in the range of from 10 μm to 50 μm, modeling canbe precisely conducted free of peeling. Therefore, the layer isrepetitively formed until the thickness of the laminated layers reachesthe height of the 3D object to be manufactured.

The method of manufacturing a 3D object relating to a third embodimentpreferably includes a step of forming a first modeled portion and a stepof forming a second modeled portion, and other optional steps.

Step of Forming First Modeled Portion

The step of forming the first modeled portion includes placing the firsthydrogel liquid precursor on a base plate (substrate) and curing thefirst hydrogel liquid precursor placed on the base plate.

With regard to the step of placing the first hydrogel liquid precursoron the base plate, the detailed description is omitted because theplacing step is the same as the placing step of the first hydrogelliquid precursor on the base plate in the method of manufacturing the 3Dobject relating to the second embodiment.

The first hydrogel liquid precursor in the liquid set for 3D modeling ofthe present disclosure can be used as the first hydrogel liquidprecursor.

The device to cure the first hydrogel liquid precursor on the base platehas no particular limit. For example, the curing step is the same as thecuring step of the first hydrogel liquid precursor in the method ofmanufacturing the 3D object relating to the second embodiment.

Step of Forming Second Modeled Portion

The step of forming the second modeled portion includes placing thesecond hydrogel liquid precursor having the different composition fromthe first hydrogel liquid precursor on an area other than the area wherethe first hydrogel liquid precursor is placed and curing the secondhydrogel liquid precursor placed on the base plate.

The second hydrogel liquid precursor may be the same as the firsthydrogel liquid precursor except for the composition. “The secondhydrogel liquid precursor has a different composition from the firsthydrogel liquid precursor” means that either or both of the kind and thecontent of the composition constituting the second hydrogel liquidprecursor is different from the first hydrogel liquid precursor. Thismakes it possible to manufacture a hydrogel modeling object havingportions having different modulus of elasticity (80 percent compressivestress-strain) when both the first hydrogel liquid precursor and thesecond hydrogel liquid precursor are cured. Although depending on thepurpose of application, one of the cured portions from the firsthydrogel liquid precursor and the second hydrogel liquid precursor hasan 80 percent compressive stress-strain of 0.4 mPa or more. The 80percent compressive stress-strain can be measured by, for example, auniversal tester (AG-I, manufactured by Shimadzu Corporation).

“Placing the second hydrogel liquid precursor on an area other than thearea where the first hydrogel liquid precursor is placed” means that theposition where the second hydrogel liquid precursor is placed does notoverlap on the position where the first hydrogel liquid precursor isplaced but the positions can be adjacent to each other.

The second hydrogel liquid precursor in the liquid set for 3D modelingof the present disclosure can be used as the second hydrogel liquidprecursor.

The method of placing the second hydrogel liquid precursor is notparticularly limited. Preferably, droplets formed of the second hydrogelliquid precursor are applied to target positions with appropriateprecision by the method. For example, a dispenser method, a spraymethod, or an inkjet method can be suitably selected to a particularlyapplication.

Curing of the first hydrogel liquid precursor on the base plate andcuring of the second hydrogel liquid precursor on the base plate can beconducted at the same time or separately. In terms of productionefficiency, it is preferable to conduct both curing at the same time.

Other Optional Steps

The other optional steps are not particularly limited and include forexample, placing and curing a liquid for a hard modeling object(support) that becomes a hard modeling object to support a 3D object ona position on the base plate other than the positions of the first hardmodeling object and the second hard modeling object, data processing ofacquiring and processing three-dimensional data, removing the 3D objectfrom the hard modeling object, cleaning the 3D object, and polishing the3D object.

The liquid for a hard modeling object (support) in the liquid set for 3Dmodeling of the present disclosure can be used as the liquid for a hardmodeling object (substrate).

“Placing the liquid for a hard modeling object on a position on the baseother than the positions of the first hydrogel liquid precursor and thesecond hydrogel liquid precursor” means that the position where theliquid for a hard modeling object is placed does not overlap on thepositions where the first hydrogel liquid precursor and the secondhydrogel liquid precursor are placed but the position of the liquid fora hard modeling object may be adjacent to the positions of the firsthydrogel liquid precursor and the second hydrogel liquid precursor.

The method of placing the liquid for a hard modeling object on the baseis not particularly limited. Preferably, droplets formed of the liquidfor a hard modeling object are applied to target positions withappropriate precision by the method. For example, a dispenser method, aspray method, or an inkjet method can be suitably selected to aparticularly application.

In the method of manufacturing a 3D object relating to the thirdembodiment, each step described above may be repeated multiple times.When repeating each step, the number of the repetition to form a 3Dobject by laminating layers on the base plate is not simply determinedbecause the number depends on the side, form, structure, etc. of the 3Dobject to be manufactured. However, if the thickness per layer is in therange of from 10 μm to 50 μm, modeling can be precisely conducted freeof peeling. Therefore, the layer is repetitively formed until thethickness of the laminated layers reaches the height of the 3D object tobe manufactured.

As for the data processing step, for example, the method disclosed inJapanese Patent No. 5239037 can be used. In the present disclosure, fromacquiring data to discharging each liquid using the liquid set for 3Dmodeling is conducted as follows.

First, three-dimensional surface data or solid data designed bythree-dimensional computer-aided designing system (CAD) or taken in by athree-dimensional scanner or digitizer are converted into standardtriangulated language (STL) format to obtain various data. Thereafter,the obtained data are input into a device for 3D modeling. Based on thevarious kinds of input data, the direction of 3D modeling is determinedfor a 3D object to be modeled. The direction is not particularlylimited. Normally, it is preferable to select a direction in which Zdirection (height direction) is the lowest.

After determining the direction of the modeling, the projected areas inX-Y plane, X-Z plane, and Y-Z plane of the three-dimensional form areobtained. To reinforce the thus-obtained block form, each plane exceptfor the upper plane of the X-Y plane is transferred to the outsidedirection in a suitable amount. The transfer amount is not particularlylimited and is, for example, about 1 mm to about 10 mm althoughdepending on the form, the size, and material. The block form enclosingthe form to be modeled is identified except for the upper plane.

This block form is sliced in the Z direction with a thickness of asingle layer. The thickness of a single layer varies depending onmaterials and cannot be simply determined but is preferably from 10 μmto 50 μm. When only one 3D object is manufactured, this block form isplaced in the center of the Z stage (i.e., table on which the modeledobject lowered a single layer by a single layer for each layer formingis placed).

In addition, when a plural of 3D objects are manufactured at the sametime, the block forms are arranged on the Z stage. Also, the block formscan be piled up. It is possible to automatically create the block forms,the sliced data (contour line data), and the placement on the Z stage ifmaterials to be used are determined.

Next, by the in-or-out decision (whether to jet each liquid of theliquid set for 3D modeling described above on the contour) withreference to the outermost contour line of the sliced data, thepositions where each liquid is jetted in an inkjet method arecontrolled.

The sequence of jetting the liquids in the liquid set for 3D modelingis, for example, when liquids from the first to the liquid for hardmodeling object are used, it is preferable to jet the liquid for hardmodeling object first and thereafter at least one of the first hydrogelliquid precursor and the second hydrogel liquid precursor. If theliquids are jetted in this sequence, storage portions such as guttersand dams are formed by the liquid for hard modeling object. Thereafter,at least one of the first hydrogel liquid precursor and the secondhydrogel liquid precursor are jetted into the storage portion, so thateven if materials which are liquid at room temperature are used as thefirst hydrogel liquid precursor and the second hydrogel liquidprecursor, the liquid does not drip off. Therefore, a wide variety ofphotocurable resins, thermocuring resins, etc. can be used.

In addition, to shorten the modeling time, it is preferable to jet atleast one of the first hydrogel liquid precursor, the second hydrogelliquid precursor, and the liquid for hard modeling object in each ofoutward and return routes of integrated inkjet heads for lamination.Furthermore, by using a mechanism having an active energy ray irradiator(for example, ultraviolet irradiator) adjacent to an inkjet head to jeteach liquid of the liquid set for 3D modeling, the time to be taken forsmoothing treatment is omitted, thereby speeding up the modeling.

As described above, in the method of manufacturing a 3D object of thepresent disclosure, the liquid is discharged through fine holes by aninkjet method or disperser method so that the liquid is applied to forman image for a single layer. Therefore, at least one of the firsthydrogel liquid precursor and the second hydrogel liquid precursor isclearly separated from and not mixed with the liquid for hard modelingobject at the border before curing (non-compatible state).

In typical modeling methods, at least one of the first hydrogel liquidprecursor and the second hydrogel liquid precursor is compatibilizedwith the liquid for hard modeling object at contact portions so that theborder is not clear when photopolymerized. As a result, fineconcavo-convex portions remain on the surface of the thus-obtained 3Dobject. To the contrary, according to the method of manufacturing a 3Dobject of the present disclosure, the border after photopolymerizationis clear because at least one of the first hydrogel liquid precursor andthe second hydrogel liquid precursor is not compatible with the liquidfor hard modeling object. Furthermore, due to the difference of hardnessbetween the thus-obtained 3D object and the hard modeling object, the 3Dobject is easily separated (peeled) from the hard modeling object.Therefore, the surface smoothness of the 3D object is improved, therebycompletely or significantly omitting the polishing step after modeling.

It is preferable that, in the hydrogel modeling object manufactured bythe method of manufacturing a 3D object of the present disclosure, thefirst modeled portion (modeled portion A) should completely contain thesecond modeled portion (modeled portion B) as described in FIGS. 4A and4B. “The modeled portion A should completely contain the second modeledportion B” means the first modeled portion is wholly adjacent andencloses the second modeled portion.

The hydrogel modeling object obtained by the method of manufacturing a3D object is highly elastic and has a complex internal structurerepresented by internal organ modes. Therefore, this object is suitableas the internal organ model. The internal organ model truly reproducesthe internal structure of vessels and areas of pathology havingdifferent hardness and modulus of elasticity and the bite and touch ofthe model are extremely close to those of an internal organ.Furthermore, since the model can be cut open by a surgical scalpel, themodel is particularly suitable for procedure practice.

Device for 3D Modeling

FIG. 2 is a schematic diagram illustrating an example of the device for3D modeling for use in the present disclosure.

A device for 3D modeling illustrated in FIG. 2 jets at least one of thefirst hydrogel liquid precursor and the second hydrogel liquid precursorfrom jetting head units 29 and 30 for modeling and the liquid for hardmodeling object from jetting head units 31 and 32 for support using headunits in which inkjet heads are arranged. The device also laminates eachliquid of the liquid set for 3D modeling while curing the liquid setwith adjacent ultraviolet ray irradiators 33 and 34.

The liquid for a hard modeling object is jetted from the jetting headunits 31 and 32 for support and solidified to form a first substratelayer having a storage portion. Thereafter, at least one of the firsthydrogel liquid precursor and the second hydrogel liquid precursor isjetted from the head units 29 and 30 for 3D modeling to the storageportion of the first substrate layer and irradiated with an activeenergy ray to form a first modeling object layer. The liquid for a hardmodeling object is jetted onto the first substrate layer and solidifiedto form the second substrate layer having a storage portion on the firstsubstrate layer. Thereafter, at least one of the first hydrogel liquidprecursor and the second hydrogel liquid precursor is jetted onto thestorage portion of the second substrate layer and irradiated with anactive energy ray to form a second modeling object layer on the firstmodeling object layer to form a 3D object 35.

When the multi-head unit moves in the direction indicated by the arrowA, a support 36 and the 3D object 35 are formed on a 3D object baseplate (substrate) 37 using the jetting head unit 31 for substrate, thejetting head units 29 and 30 for 3D modeling, and the ultraviolet rayirradiator 34. The jetting head unit 32 for support and the ultravioletray irradiator 33 may be auxiliarily used.

When the multi-head unit moves in the direction indicated by the arrowB, the support 36 and the 3D object 35 are formed on the 3D object baseplate 37 using the jetting head unit 32 for support, the jetting headunits 29 and 30 for 3D modeling, and the ultraviolet rate irradiator 33.The jetting head unit 31 for support and the ultraviolet ray irradiator34 may be auxiliarily used.

Furthermore, to keep the gap between the jetting head units 29 and 30for 3D modeling, the jetting head units 31 and 32 for support, and theultraviolet ray irradiators 33 and 34 and the 3D object 35 and thesubstrate 36, a stage 38 is lowered to the number of lamination.

FIG. 3 is a schematic diagram illustrating another example of the 3Dobject manufacturing mechanism to improve smoothness of each layer incomparison with that illustrated in FIG. 2. Basically, the process isthe same as in FIG. 2 but unlike the configuration illustrated in FIG.2, the ultraviolet ray irradiators 33 and 34 are disposed between thejetting head units 29 and 30 for 3D modeling and the jetting head units31 and 32 for support.

In addition, in the device 39 for 3D modeling, the ultraviolet rayirradiators 33 and 34 are used in both directions of the arrows A and B.Due to heat generated upon application of ultraviolet ray, the surfaceof the liquid for the laminated hard modeling object is smoothed,thereby improving the dimension stability of the hydrogen modelingobject.

In addition, the device 39 for 3D modeling may furthermore includedevices for collecting ink, recycling, etc. Also, the device 39optionally includes a blade to remove each of the liquid precursors ofthe liquid set for 3D modeling attached to the nozzle surface ordetector to detect un-discharging nozzles. Furthermore, it is preferableto control the environment temperature in the device 39 during modeling.

Hydrogel Modeling Object

The hydrogel modeling object includes an inorganic mineral, a phosphonicacid compound, a polymer, preferably a solvent, and other optionalcomponents.

Inorganic Mineral

The inorganic mineral contained in the hydrogel liquid precursor can beused as the inorganic mineral.

The content of the inorganic mineral is preferably 15 percent by mass ormore, preferably from 15 percent by mass to 40 percent by mass, and morepreferably from 15 percent by mass to 25 percent by weight to the totalamount of hydrogel modeling object. When the content is 15 percent bymass or more, it is possible to increase the modulus of elasticity ofthe hydrogel modeling object.

The content of the inorganic mineral can be obtained by heating anddrying the hydrogel modeling object by a thermal analyzer (TG/DTA,manufactured by Rigaku Corporation) followed by analysis on the residualcomponent.

Polymer

As the polymer, polymers having, for example, an amide group, an aminogroup, a hydroxyl group, a tetramethyl ammonium group, a silanol group,an epoxy group, etc. are suitable and the polymer is preferably watersoluble.

Homopolymers (monopolymers), heteropolymers (copolymers), modifiedresins, or forms of salts are also allowed. Also, known functionalgroups can be introduced into these. Of these, homoplymers arepreferable.

Water-solubility of the polymer in the present disclosure means, forexample, when 1 g of the polymer is mixed with and stirred in 100 g ofwater at 30 degrees C., 90 percent by mass or more of the polymer isdissolved in water.

The polymer is obtained by polymerizing the monomer. The hydrogelmodeling object is preferably formed of a hydrogel containing a solventin a three-dimensional network structure formed by cross-linking theinorganic mineral dispersed in the solvent with the polymer obtained bypolymerizing the monomer.

Phosphonic Acid Compound

The phosphonic acid contained in the hydrogel liquid precursor can beused as the phosphonic acid compound.

Solvent

The solvent that can be used for the hydrogel modeling object can beused as the solvent. Of these, water is preferable.

Properties of Hydrogel Modeling Object

The hydrogel modeling object of the present disclosure preferably has an80 percent compressive stress-strain of 1.0 MPa or more, more preferably2.0 MPa or more, and particularly preferably 3.0 MPa or more. The upperlimit is not particularly limited and suitably determined to aparticular application. For example, 10 MPa or less is preferable for aninternal organ model. When the 80 percent compressive stress-strain is1.0 Mpa or more, the hydrogel modeling object is highly elastic andreproduces hardness close to textures of a live body. That is, a morereal internal organic model can be provided.

The modulus of compressive elasticity of the hydrogel modeling object ispreferably from 0.1 MPa to 1.0 MPa and more preferably from 0.3 MPa to0.8 MPa. When the modulus of compressive elasticity is within thepreferable range specified above, the hydrogel modeling object is highlyelastic and reproduces hardness close to textures of a live body. Thatis, a more real internal organic model can be provided.

The 80 percent compressive stress-strain and the modulus of compressiveelasticity can be measured by, for example, a universal tester (AG-I,manufactured by Shimadzu Corporation). The 80 percent compressivestress-strain and the modulus of compressive elasticity are measured byproviding a load cell of 1 kN and a compression jig for 1 kN to theuniversal tester. The sample for use in measuring by the universaltester has a form of a cube having a dimension of 10 mm×10 mm×10 mm.

The hydrogel modeling object of the present disclosure has a firstmodeled portion including the first hydrogel modeling object as thefirst modeling object and the second modeled portion including thesecond hydrogel modeling object having a different modulus of elasticity(80 percent compressive stress-strain or modulus of compressiveelasticity) from that of the first hydrogel modeling object.

As a result, the thus-obtained hydrogel modeling object has portionshaving different modulus of elasticity (80 percent compressivestress-strain or modulus of compressive elasticity) therein. In thehydrogel modeling object, the first modeled portion may completelycontain the second modeled portion or vice versa. Alternatively, thefirst modeled portion or the second modeled portion may be exposed. A 3Dobject in which one modeled portion wholly contains the other isparticularly efficiently manufactured by a method laminating hydrogelthin layers formed by discharging and curing each liquid precursor by aninkjet method.

Having generally described preferred embodiments of this invention,further understanding can be obtained by reference to certain specificexamples which are provided herein for the purpose of illustration onlyand are not intended to be limiting. In the descriptions in thefollowing examples, the numbers represent weight ratios in parts, unlessotherwise specified.

EXAMPLES

Next, the present disclosure is described in detail with reference toExamples but is not limited thereto.

Example 1 Manufacturing of Hydrogel Liquid Precursor 1

Based on the compositions shown in Table 1, [Hydrogel liquid precursor1] was prepared as follows.

Preparation of Water

Pure water was prepared by evacuating deionized water for ten minutes.

Preparation of Liquid of Initiator

An aqueous solution was prepared as [Liquid 1 of initiator] bydissolving a photopolymerization initiator (IRGACURE 184, manufacturedby BASF) in ethanol in a ratio of 4 parts of the photopolymerizationinitiator to 96 parts of ethanol.

An aqueous solution was prepared as [Liquid 2 of initiator] bydissolving sodium peroxodisulfate (manufactured by Wako Pure ChemicalIndustries, Ltd.) in pure water in a ratio of 2 parts of thephotopolymerization initiator to 98 parts of ethanol.

Tetraethyl methylene diamine (manufactured by Wako Pure ChemicalIndustries, Ltd.) was used as [Liquid 3 of initiator].

Preparation of Hydrogel Liquid Precursor 1

While stirring 165 parts of pure water, 20 parts of synthesizedhectorite (laponite XLG, manufactured by RockWood) having a compositionof [Mg_(5.34)Li_(0.66)Si₈O₂₀(OH)₄]Na⁻ _(0.66) as laminate mineral wasslowly dripped and added to the pure water followed by stirring toprepare a liquid dispersion.

Next, 0.8 parts of etidronic acid aqueous solution (CHELEST PH-210,content of effective component: 60 percent by mass, manufactured byCHELEST CORPORATION) was added to the thus-obtained liquid dispersion.Subsequent to 30-minute dispersion, 20 parts of the synthesizedhectorite was furthermore gradually added thereto followed by 30-minutestirring. 40 parts of the synthesized hectorite was added in total.Thereafter, the liquid dispersion was stored in a constant temperaturetank at 50 degrees C. for ten hours to stabilize the dispersion.

Next, 20 parts of acryloyl morpholine (ACMO, manufactured by KJChemicals Corporation) from which the polymerization inhibitor wasremoved by passing through active alumina column as the monomer and 30parts of glycerin were added to the thus-obtained liquid dispersion.Furthermore, 10 parts of EMALGEN SLS-106 (manufactured by KaoCorporation) serving as surfactant was admixed with the resultant.

Next, 2.2 parts of the [Liquid 1 of initiator] and 0.15 parts of the[Liquid 3 of initiator] were added to the mixture while being cooleddown. Subsequent to stirring and mixing, the resultant was subject toevacuation for 20 minutes. Thereafter, impurities were removed byfiltration to prepare [Hydrogel liquid precursor 1].

Storage Stability

The thus-obtained [Hydrogel liquid precursor 1] was placed inpolypropylene bin (50 ml) and left in a constant temperature tank at 50degrees for 24 hours. The [Hydrogel liquid precursor 1] was taken out ofthe constant temperature tank and left until the temperature of the[Hydrogel liquid precursor 1] was down to room temperature (25 degreesC.). The initial viscosity of [Hydrogel liquid precursor 1] was measuredunder 1 atm.

The [Hydrogel liquid precursor 1] was placed in a polypropylene bin (50ml), left in a constant temperature tank at 50 degrees C. for two weeks,and thereafter taken out from the tank. The [Hydrogel liquid precursor1] taken out of the constant temperature tank was left and cooled downto room temperature (25 degrees C.) followed by measuring the two-weekviscosity at 1 atm. The ratio of the two-week viscosity to the initialviscosity was calculated.

The measuring results of the initial viscosity and the two-weekviscosity and the calculation results of the ratio of the two-weekviscosity to the initial viscosity are shown in Table 1.

The initial viscosity and the two-week viscosity were measured by arotation viscometer (VISCOMATE VM-150 III, manufactured by TOKI SANGYOCO., LTD.).

Compression Test

The thus-obtained [Hydrogel liquid precursor 1] was irradiated with alight amount of 350 mJ/cm² by an ultraviolet irradiator (SPOT CURESP5-250DB, manufactured by USHIO INC.) to manufacture [Hydrogel modelingobject 1]. 80 percent compressive stress-strain and modulus ofcompressive elasticity of the thus-obtained [Hydrogel modeling object 1]were measured as follows: The results are shown in Table 1.

[Hydrogel modeling object 1] having a form of 10 mm×10 mm×10 mm wasplaced in a universal tester (AG-1, manufactured by SHIMADZUCORPORATION). The stress to the compression applied to the load cell ofthe universal tester mentioned above was recorded by a computer to plotthe stress to the amount of displacement.

When the hydrogel modeling object was fractured, the modulus ofcompressive elasticity at the time of the fracture was determined as themaximum value. The 80 percent compressive stress-strain was shown forthe un-fractured hydrogel modeling object.

In addition, the modulus of compressive elasticity of the hydrogelmodeling object was obtained from the measuring data from the sameuniversal tester. The modulus of compressive elasticity was calculatedas the gradient at 10 percent displacement taken as the differencebetween 10 percent compressive stress-strain and 20 percent compressivestress-strain.

Examples 2 to 7

[Hydrogel liquid precursor 2] to [Hydrogel liquid precursor 7] wereprepared in the same manner as in Example 1 except that the compositionand the blending amount of Example 1 were changed to the compositionsand the blending amounts shown in Table 1.

With regard to the thus-obtained [Hydrogel liquid precursor 2] to[Hydrogel liquid precursor 7], the initial viscosity and the two-weekviscosity were measured in the same manner as in Example 1 and the ratioof the two-week viscosity to the initial viscosity was calculated. Theresults are shown in Table 1.

Next, using the obtained [Hydrogel liquid precursor 2] to [Hydrogelliquid precursor 7], [Hydrogel modeling object 2] to [Hydrogel modelingobject 7] were manufactured in the same manner as [Hydrogel modelingobject 1].

The compression test was conducted for the [Hydrogel modeling object 2]to [Hydrogel modeling object 7] in the same manner as the [Hydrogelmodeling object 1]. The results are shown in Table 1.

TABLE 1 Example Component (parts by mass) 1 2 3 4 5 6 7 Hydrogel liquidprecursor No. 1 2 3 4 5 6 7 Hydrogel No. 1 2 3 4 5 6 7 Inorganic XLG 4040 40 40 40 40 40 mineral Monomer ACMO 20 20 20 20 20 20 20 PhosphonicEtidronic acid 0.8 0.8 — — — — 0.8 acid Etidronic acid — — 0.32 — — — —compound disodium Etidronic Acid — — — 0.32 — — — tetra-sodiumAlendronic — — — — 0.32 — — acid Methylene — — — — — 0.32 — diphosphonicacid Surfactant EMULGEN 1 1 1 1 1 1 1 SLS-106 Liquid 1 of IRGACURE 2.22.2 2.2 2.2 2.2 2.2 — initiator 819 (4 percent in EtOH) Liquid 2 ofSodium — — — — — — 5 initiator peroxodisulfate (2 percent aq) Liquid 3of Tetraethyl 0.15 0.15 0.15 0.15 0.15 0.15 0.15 initiator methylenediamine Solvent Glycerin 30 30 30 30 30 30 30 Water Deionized 165 165165 165 165 165 165 water Property of Initial viscosity 12.5 13.5 13.812.9 14.2 13.9 12.2 hydrogel (mPa · s) liquid Two-week 12.3 13.8 13.813.4 14.6 13.9 12.6 precursor viscosity (mPa · s) Two-week 1.0 1.0 1.01.0 1.0 1.0 1.0 viscosity/ Initial viscosity Property of Modulus of 0.750.69 0.72 0.68 0.73 0.23 0.85 hydrogel compressive elasticity (MPa) 80percent 4.3 3.8 3.2 3.7 3.8 4.1 6.5 compressive stress-strain (MPa)

The details of the phosphonic acid compounds shown in Table 1 were asfollows:

Etidronic Acid Disodium (manufactured by CHELEST CORPORATION)

Etidronic Acid tetrasodium (manufactured by CHELEST CORPORATION)

Alendronic acid (Tokyo Chemical Industry Co. Ltd.)

Methylene diphosphonic acid (Tokyo Chemical Industry Co. Ltd.)

Comparative Examples 1 to 5

[Hydrogel liquid precursor 8] to [Hydrogel liquid precursor 12] wereprepared in the same manner as in Example 1 except that the compositionand the blending amount of Example 1 was changed to the compositions andthe blending amounts shown in Table 2.

Next, using the obtained [Hydrogel liquid precursor 8] to [Hydrogelliquid precursor 12], [Hydrogel modeling object 8] to [Hydrogel modelingobject 12] were manufactured in the same manner as [Hydrogel modelingobject 1].

The compression test was conducted for the [Hydrogel modeling object 8]to [Hydrogel modeling object 12] in the same manner as the [Hydrogelmodeling object 1]. The results are shown in Table 2.

TABLE 2 Comparative Example Component (parts by mass) 1 2 3 4 5 Hydrogelliquid precursor No. 8 9 10 11 12 Hydrogel No. 8 9 10 11 12 InorganicXLG 40 40 40 40 40 mineral Monomer ACMO 20 20 20 20 20 PhosphonicPyrophosphoric 0.32 — — 0.72 — acid acid Phytic acid — 0.32 — — — NTMP —— 0.32 — — Surfactant EMULGEN 1 1 1 1 1 SLS-106 Water IRGACURE 2.2 2.22.2 2.2 2.2 819 Liquid 1 of Deionized water 165 165 165 165 165initiator Property of Initial viscosity 12.3 368 152 Gelated Gelatedhydrogel (mPa · s) liquid Two-week viscosity Gelated Gelated GelatedGelated Gelated precursor (mPa · s) Two-week viscosity/  —*  —*  —*  —* —* Initial viscosity Property of Modulus of 0.09  —**  —**  —**  —**hydrogel compressive elasticity (MPa) 80 percent 1.2  —**  —**  —**  —**compressive stress-strain (MPa) —* represents “unable to calculate dueto gelation” —** represents “unable to measure”

The details of the phosphonic acid compounds shown in Table 2 were asfollows:

Pyrophosphoric acid (manufactured by Sigma-Aldrich Japan K.K.)

Phytic acid (manufactured by Tokyo Chemical Industry Co. Ltd.)

Nitrilotris (Methylene Phosphonic Acid (NTMP, manufactured CHELESTCORPORATION)

In Comparative Examples 2 and 3 shown in Table 2, hydrogels were notmodeled from [Hydrogel liquid precursor 9] or [Hydrogel liquid precursor10] because these liquids had excessively high initial viscosity. Inaddition, [Hydrogel liquid precursor 11] and [Hydrogel liquid precursor12] of Comparative Examples 4 and 5 were gelated during preparation ofthe hydrogel liquid precursor so that it was not possible to preparehydrogel liquid precursors or measure the viscosity thereof.

Example 8

Using the [Hydrogel liquid precursor 1] and [Hydrogel liquid precursor2] and the device for 3D modeling illustrated in FIG. 2, [3D object 1]illustrated in FIGS. 4A and 4B were manufactured. First, the 3D data ofthe 3D object as illustrated in FIGS. 4A and 4B were input into thedevice for 3D modeling.

The two tanks communicating with the inkjet heads of the device for 3Dmodeling (MH2420, manufactured by Ricoh Industry Company, Ltd.) werefilled with the [Hydrogel liquid precursor 1] and [Hydrogel liquidprecursor 2] and the two kinds of hydrogel precursor liquids were jettedfrom each inkjet heads to place the [Hydrogel liquid precursor 1] and[Hydrogel liquid precursor 2] on a base plate.

Next, the [Hydrogel liquid precursor 1] and [Hydrogel liquid precursor2] placed on the base plate were irradiated with a light amount of 1,000mJ/cm₂ by an ultraviolet irradiator (SubZero055, manufactured byIntegration Technology Ltd.) to cure the [Hydrogel liquid precursor 1]and [Hydrogel liquid precursor 2] on the base plate. This series ofsteps were repeated to manufacture (model) the [3D object 1].

The thus-obtained [3D object] was cut to obtain cubes of 10 mm×10 mm×10mm from the portions corresponding to the modeled portion B and themodeled portion A and the modulus of elasticity (80 percent compressivestress-strain and modulus of compressive elasticity) for each wasmeasured. The modeled portion A had the modulus of elasticity (80percent compressive stress-strain and modulus of compressive elasticity)around that of the [Hydrogel modeling object 1] and the modeled portionB had the modulus of elasticity (80 percent compressive stress-strainand modulus of compressive elasticity) around that of the [Hydrogelmodeling object 2].

Example 9 Preparation of Liquid for Hard Modeling Object (Support)

A total content of 300 grams including 10 parts of urethane acrylate(product name: DIABEAM UK6038, manufactured by Mitsubishi Rayon Co.,Ltd.) as curable material, 90 parts of neopentyl glycol hydroxy pivalicacid ester dimethacrylate (product name: KAYARAD MANDA, manufactured byNippon Kayaku Co., Ltd.) as curable material, 3 parts ofphotopolymerization initiator (product name: IRGACURE 184, manufacturedby BASF), and 2 parts of blue pigment (product name: Lionol Blue 7400G,manufactured by TOYO INK CO., LTD.) as colorant were dispersed at 2,000rotation per minute (rpm) using a Homogenizer (HG30, manufactured byHitachi Koki Co., Ltd.) until a uniform mixture was obtained.Thereafter, the mixture was filtered to remove impurities followed byevacuation in vacuum for ten minutes to obtain a liquid for hardmodeling object (support).

Using the [Hydrogel liquid precursor] and the [Hydrogel liquid precursor4], and the liquid for hard modeling object, data processing wasconducted according to the description of Japanese Patent No. 5239037 bythe device for 3D modeling illustrated in FIG. 2 to obtain thethree-dimensional model data of a liver. Based on the model data, aninternal organ model of the liver of a pig was manufactured (modeled).

The thus-obtained internal organ model of the liver was almost true tolife of a real liver of the pig about form, touch, and elasticity.

Embodiments of the present disclosure are, for example, as follows.

-   -   1. A hydrogel liquid precursor includes an inorganic mineral and        a monomer, wherein the inorganic mineral accounts for 15 percent        by mass or more of the hydrogel liquid precursor, wherein the        hydrogel liquid precursor has an initial viscosity of 20 mPa·s        or less at 25 degrees C., wherein the hydrogel liquid precursor        has a ratio of a two-week viscosity to the initial viscosity of        from 0.90 to 1.10, the two-week    -   2. viscosity representing a viscosity of the hydrogel liquid        precursor at 25 degrees C. after being left at 50 degrees C. for        two weeks.    -   2. The hydrogel precursor liquid according to 1 mentioned above,        further includes a phosphonic acid compound.    -   3. The hydrogel precursor liquid according to 2 mentioned above,        wherein the phosphonic acid compound is represented by the        following Chemical formula 1.

where R represents a substituted or non-substituted divalentsubstitution group.

-   -   4. The hydrogel precursor liquid according to 3 mentioned above,        wherein R in the Chemical formula 1 includes —(R₁)C(R₂)—, where        R₁ and R₂ each, independently represent substituted or        non-substituted alkyl groups.    -   5. The hydrogel precursor liquid according to 3 or 4 mentioned        above, wherein R in the Chemical formula 1 includes        —(OH)C(CH₃)—.    -   6. The hydrogel precursor liquid according to any one of 1 to 5        mentioned above, wherein the monomer includes an active energy        ray polymerizable monomer.    -   7. A method of manufacturing a three-dimensional object includes        manufacturing a hydrogel modeling object using the liquid set of        any one of 1 to 6 mentioned above.    -   8. A liquid set for three-dimensional modeling includes a first        hydrogel liquid precursor including a first inorganic mineral        and a first monomer, wherein the first inorganic mineral        accounts for 15 percent by mass or more of the first hydrogel        liquid precursor, wherein the first hydrogel liquid precursor        has an initial viscosity of 20 mPa·s or less at 25 degrees C.,        wherein the first hydrogel liquid precursor has a ratio of a        two-week viscosity to the initial viscosity of from 0.90 to        1.10, the two-week viscosity representing a viscosity of the        first hydrogel liquid precursor at 25 degrees C. after being        left at 50 degrees C. for two weeks, and a second hydrogel        liquid precursor including a second inorganic mineral and a        second monomer.    -   9. A method of manufacturing a three-dimensional object includes        manufacturing a hydrogel modeling object using the liquid set        for 3D modeling of 8 mentioned above.    -   10. The method according to 9 mentioned above, further includes        placing the first hydrogel precursor liquid, placing the second        hydrogel precursor liquid on a different position from where the        first hydrogel precursor is placed, and repeating the placing        the first hydrogel precursor and the placing the second hydrogel        precursor multiple times.    -   11. The method according to 10 mentioned above, wherein one of        the placing the first hydrogel precursor and the placing the        second hydrogel precursor is conducted by an inkjet method or a        dispenser method.    -   12. A hydrogel modeling object manufactured by the method of any        one of 7, 9, 10, and 11 has an 80 percent compressive        stress-strain of 1.0 MPa or more.    -   13. A hydrogel modeling object includes an inorganic mineral,        a phosphonic acid compound, and a polymer, wherein the inorganic        mineral accounts for 15 percent by mass or more of the hydrogel        modeling object.    -   14. The hydrogel modeling object according to 13 mentioned        above, has an 80 percent compressive stress-strain of 1.0 MPa or        higher.    -   15. The hydrogel modeling object according to 13 or 14 mentioned        above, wherein the inorganic mineral includes a laminate        mineral.    -   16. The hydrogel precursor liquid according to any one of 13 to        15, wherein the phosphonic acid compound is represented by the        following Chemical formula 1,

where R represents a substituted or non-substituted divalentsubstitution group.

-   -   17. The hydrogel modeling object according to 16 mentioned        above, wherein R in the Chemical formula 1 includes —(R₁)C(R₂)—,        where R₁ and R₂ each, independently represent substituted or        non-substituted alkyl groups.    -   18. The hydrogel modeling object according to 16 or 17 mentioned        above, wherein R in the Chemical formula 1 includes        —(OH)C(CH₃)—.    -   19. A hydrogel modeling object includes a first modeled portion        including the hydrogel modeling object of any one of 12 to 18        mentioned above and a second modeled portion including a second        hydrogel modeling object having a different modulus of        compressive elasticity from a compressive elasticity of the        hydrogel modeling object of any one of 12 to 18 mentioned above,        wherein the first modeled portion includes or is included in the        second modeled portion.    -   20. The hydrogel modeling object according to any one of 12 to        19 mentioned above, wherein the inorganic mineral includes a        laminate mineral.

According to the present disclosure, provide is an improved hydrogelliquid precursor having good storage property and suitable tomanufacture a hydrogel modeling object having a complex inner structureincluding a modeling portion having a high modulus of elasticity shapedby a hydrogel modeling object having a high modulus of elasticity with amodeling portion having a low modulus of elasticity disposed at anarbitrary area.

Having now fully described embodiments of the present invention, it willbe apparent to one of ordinary skill in the art that many changes andmodifications can be made thereto without departing from the spirit andscope of embodiments of the invention as set forth herein.

What is claimed is:
 1. A hydrogel liquid precursor comprising: aninorganic mineral; and a monomer, wherein the inorganic mineral accountsfor 15 percent by mass or more of the hydrogel liquid precursor, whereinthe hydrogel liquid precursor has an initial viscosity of 20 mPa·s orless at 25 degrees C., and wherein the hydrogel liquid precursor has aratio of a two-week viscosity to the initial viscosity of from 0.90 to1.10, the two-week viscosity representing a viscosity of the hydrogelliquid precursor at 25 degrees C. after being left at 50 degrees C. fortwo weeks.
 2. The hydrogel liquid precursor according to claim 1,wherein the monomer includes an active energy ray polymerizable monomer.3. The hydrogel liquid precursor according to claim 1, furthercomprising a phosphonic acid compound.
 4. The hydrogel liquid precursoraccording to claim 3, wherein the phosphonic acid compound isrepresented by the following Chemical formula 1,

where R represents a substituted or non-substituted divalentsubstitution group.
 5. The hydrogel liquid precursor according to claim4, wherein R in the Chemical formula 1 includes —(R₁)C(R₂)—, where R₁and R₂ each, independently represent substituted or non-substitutedalkyl groups.
 6. The hydrogel liquid precursor according to claim 4,wherein R in the Chemical formula 1 includes —(OH)C(CH₃)—.
 7. A methodof manufacturing a three-dimensional object, the method comprising:manufacturing a hydrogel modeling object using a hydrogel liquidprecursor of claim
 1. 8. A hydrogel modeling object manufactured by themethod of claim 7 and having an 80 percent compressive stress-strain of1.0 MPa or more.